蒸汽爆破玉米芯水解液脱毒及其发酵生产燃料丁醇

为探究以玉米芯为原料生产燃料丁醇的最佳工艺技术,该研究对蒸汽爆破玉米芯水解液的脱毒方式及脱毒后的水解液的丙酮丁醇发酵进行了研究。结果表明:D301树脂对玉米芯水解液进行脱毒的综合效果最好,甲酸、乙酸和总酚的脱除率分别达到60%、46.04%和56.31%,香草醛脱除率为100%,对糠醛和5-HMF的脱除率分别达到了82.95%和87.52%;同时总糖的损失率为4.38%。D301树脂脱毒后的水解液经C.acetobutylicum CICC 8016发酵丁醇和总溶剂产量分别为5.2和7.5 g/L,葡萄糖和总糖的利用率分别达到100%和73.67%。当D301树脂脱毒的玉米芯水解液初始糖的质量浓度为50 g/L时,丁醇和总溶剂(丙酮、丁醇和乙醇)的质量浓度分别达到最大9.7和14.6 g/L。该研究为利用玉米芯工业化生产燃料丁醇提供了可靠的技术支持。

Hydrolysate detoxified from steam exploded corn cob and its fermentation producing butanol fuels

Abstract: The development and utilization of biomass have been paid great attention by many countries with the depletion of fossil energy sources. Due to the recalcitrant and complex structure of lignocellulosic biomass, various pretreatment methods are adopted to help biomass carbohydrate's hydrolysis. Pretreatment can increase the biomass digestibility for efficient fermentable sugar production, but many fermentation inhibitors are also produced during this process, such as furan derivatives (furfural and 5-hydroxymethylfurfural), mini-molecule organic acid (acetic acid and formic acid), and lignin degradation products (coumaric acid, vanillin and other phenolics). Therefore, the detoxification process which removes fermentation inhibitors from hydrolysates is essential for the production of biomass energy; at the same time, for different fermentations have different adaptability of initial sugar concentration in fermentation liquor, the studies about the optimal initial sugar fermentation concentration are also meaningful. In order to study the best technology of butanol fuel production from steam exploded corn cob, 4 detoxification methods, which were over liming, D301 resin, over liming combined with D301 resin, and over liming combined with NKAII macro porous resin, were used to detoxify the hydrolysate of steam exploded corn cob, and their effects on butanol production were also determined in this research. The results showed that the D301 resin detoxification was the most efficient way to detoxify the hydrolysate of steam exploded corn cob. The removal ratio of vanillin could reach 100%; the removal ratio of formic acid, acetic acid, total phenol, furfural and 5-hydroxymethylfurfural reached 60%, 46.04%, 56.31%, 82.95% and 87.52%, respectively. At the same time, total sugar lost ratio was only 4.38%. Finally, butanol and ABE (actone, butanol, ethanol) production were 5.2 and 7.5 g/L by fermentation with C. acetobutylicum CICC 8016, and the utilization rate of glucose and total sugar reached 100% and 73.67%, respectively. When the initial sugar concentration was 50 g/L in the detoxified corn cob hydrolysate, the maximum concentrations of butanol and total solvent were 9.7 and 14.6 g/L respectively after 96 h fermentation. The over liming and over liming combined with NKAII macro porous resin had poor inhibitor removal ratio and lower butanol production (no more than 1.0 g/L butanol was produced). Although over liming combined with D301 resin had higher inhibitor removal ratio, only 2.4 g/L butanol and 3.3 g/L ABE were produced because of high sugar lost ratio (about 41.59% glucose and 15.88% xylose were lost during the detoxification). In conclusion, the D301 resin detoxification is an idea process for butanol production from lignocellulose hydrolysate because of its high microbial inhibitor removal ratio and low sugar loss. This research provides a reliable detoxification method for butanol fermentation with the hydrolysate of steam exploded corn cob.